@techreport {60771, title = {High Performance Building Fa{\c c}ade Solutions-Phase II}, year = {2014}, month = {03/2014}, abstract = {

The High Performance Building Fa{\c c}ade Solutions{\textendash}Phase II project was initiated through the California Energy Commission{\textquoteright}s Public Interest Energy Research (PIER) program in July 2010 to support industry{\textquoteright}s development and deployment of both incremental and breakthrough fa{\c c}ade technologies in partnership with the U.S. Department of Energy (DOE). The objective of this three-year project was to develop, or support the development and deployment of, promising near-term and emerging zero net energy building fa{\c c}ade technologies for solar control and daylighting, addressing two of the largest end uses in California commercial buildings: cooling and lighting. In partnership with industry (such as manufacturers), three classes of technologies were investigated: daylighting systems, angular-selective shading systems, and dynamic fa{\c c}ade systems. Commercially available and emerging prototype technologies were developed and evaluated using laboratory tests. Simulations, full-scale outdoor tests in the Advanced Window Testbed, and demonstration projects quantified energy and peak electric demand reductions and occupant satisfaction, acceptance, and comfort associated with the resultant indoor environment. Several new technologies were developed using virtual prototyping tools. Integrated control systems were developed using model predictive controls. Simulation tools were developed to model operable complex fenestration systems such as shades and microprismatic films. A schematic design tool called COMFEN was developed to facilitate evaluation of these advanced technologies in the early design phase. All three classes of technologies resulted in significant reductions in perimeter zone energy use and peak electric demand, providing viable options that can support California{\textquoteright}s long-term goal of achieving zero net energy use in the next decade.

}, keywords = {automated shading, between-pane shading, bidirectional scattering distribution functions, building energy simulation tools, Complex fenestration systems, daylighting, daylighting simulation tools, electrochromics, exterior shading, goniophotometer, light shelves, microprismatic films, model predictive controls, motorized shading, shading, solar-optical properties, switchable windows, thermochromics, virtual prototyping, window heat transfer}, author = {Eleanor S. Lee and Brian E. Coffey and Luis L. Fernandes and Sabine Hoffmann and Andrew McNeil and Anothai Thanachareonkit and Gregory J. Ward} } @techreport {61021, title = {High Performance Building Mockup in FLEXLAB}, year = {2014}, month = {12/2014}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley, CA}, abstract = {

Genentech has ambitious energy and indoor environmental quality performance goals for Building 35 (B35) being constructed by Webcor at the South San Francisco campus. Genentech and Webcor contracted with the Lawrence Berkeley National Laboratory (LBNL) to test building systems including lighting, lighting controls, shade fabric, and automated shading controls in LBNL{\textquoteright}s new FLEXLAB facility. The goal of the testing is to ensure that the systems installed in the new office building will function in a way that reduces energy consumption and provides a comfortable work environment for employees.

LBNL tested three facades of the new office building in the rotating FLEXLAB testbed: west, south and east. External shading, lighting, and internal shading control was configured for each orientation to replicate the conditions of B35. The three facades were each tested for one week three times between July and October 2014. Changes were made between each test to improve the performance of the systems.

Linear pendant LED light fixtures will illuminate the open office areas of the office building. These fixtures were installed in FLEXLAB. The wide spacing between rows of light fixtures results in a low lighting power density of 0.57 W/ft2 in the open office areas, while still meeting the average illuminance criteria of 300 lux (28 footcandles). A combination of the wide spacing and optics of the light fixture creates a nonuniform lighting pattern on the ceiling of the space. Changing to a diffuse lens on the uplight will help reduce abrupt changes in luminance on the ceiling but non-uniformity will persist due to the wide spacing.

The pendant light fixtures allow separate control of the downward and upward light. The lighting control design aims to enhance the quality of space by dimming upward light unison providing uniform patterns of electric light on the ceiling. The downward light of each fixture dims to provide just enough light to meet illuminance criteria below the fixture.

Webcor installed two lighting control systems manufactured by Enlighted and Encelium for testing in FLEXLAB. The Encelium system uses an open loop control architecture with a ceiling-mounted photosensor at each facade (inside of the automated shade). While there is greater variation in workplane illuminance provided by the Encelium system, the system is better able to control upward versus downward lighting and is able to control the lighting according to the lighting design intent. The architecture of the Encelium system offers more functional flexibility by allowing any input (sensors, switches etc.) or multiple inputs to affect any fixture.

The Enlighted control system uses closed loop architecture with two photosensors per fixture (one for upward light and one for downward light). The Enlighted system controlled the lights more precisely than the Encelium system to meet workplane illuminance requirements, however the upward versus downward light control did not behave according to the lighting design intent.

MechoSystems provided motorized window shades and automated control. The shades in each window had a different color fabric, one dark grey and one medium grey. Both shade fabrics were an open weave with 3\% openness. Genentech selected the dark colored shade because it provides a better view of the exterior compared to the lighter colored shade. Anecdotal evidence suggests that some occupants may experience direct glare with 3\% open fabric while other occupants will not experience glare under the same conditions. Visual discomfort during the worst case sunny winter condition was not evaluated. However, the east-facing orientation during the equinox period was exposed to low sun angles in the third test period so findings of just acceptable visual discomfort are expected to be similar to what might be experienced during the winter.

The shades operated as expected on sunny days (which was the predominant condition during the test period). The testing identified substantial potential energy savings for the lighting systems by stopping the shade above the sill, preventing the shade from completely covering the window and allowing the sun to shine deeper into the space through the bottom few inches of the window. On partly cloudy days, which occurred more frequently after our testing concluded, anecdotal evidence suggests that the shades could be raised more often. LBNL suggests that a second threshold be implemented which drops the shade partway to prevent direct glare from bright sun, but doesn{\textquoteright}t close the shade down to the height required to limit sunshine depth.

Thermal comfort analysis suggests that occupants seated near the shaded window will be comfortable around 80\% of the time. The 20\% of time where the observed conditions fall outside the ASHRAE Standard 55 are almost always due to occupants being cold in the morning. This discomfort is mostly driven by cold surrounding surfaces causing a low mean radiant temperature and overcooling from outside air during economizer mode. Only one thermal comfort station, located near the facade, was used for the experiment. Thermal comfort further from the facade is unknown but is likely to be better due to the increased distance from the relatively cold facade.

Visual comfort studies indicated that occupants could sit as close as 3.5 feet to the east and west facade and 2.5 feet to the south facade when facing parallel to the window. Occupants must sit further away from the window to be comfortable when facing the window directly. Occupants should be 3.5 feet away when facing the south facade, 4.5 feet away when facing the west facade and 5.5 feet away when facing the east facade. Thermal comfort studies show that sitting within 30 inches of the facade has a negligible effect on comfort ratings.

Daylighting controls reduced lighting energy use in FLEXLAB by 46\% for east facade, 34\% for south facade and 35\% for west facade over 30 feet deep perimeter zone between 7 AM and 7 PM local time at autumn equinox. Occupancy controls will further reduce lighting energy use, though they were not implemented for the test due to the cell being tested unoccupied.

Genentech, Webcor, and the architectural and engineering team had access to the FLEXLAB during and for a month following the test period to observe, work, and discuss operational issues with employees and staff. The project team made their own qualitative observations about the space in terms of view, adequacy of lighting and daylight levels, color, furniture placement, etc. The project team worked collaboratively with the LBNL team to fine tune details of component design, control settings, troubleshooting, and operations. Because Genentech is introducing a new model for their work environment, a non-assigned workplace, there were detailed discussions on how to educate the occupants about the new technologies and their operational modes. Commissioning and tuning procedures were also discussed.

}, keywords = {commercial buildings, daylighting, energy management control systems, exterior shading, field test, lighting controls, monitored evaluation, shading controls, thermal comfort, visual comfort}, author = {Andrew McNeil and Christian Kohler and Eleanor S. Lee and Stephen E. Selkowitz} } @article {2964, title = {An Hourly-Based Performance Comparison of an Integrated Micro-Structural Perforated Shading Screen with Standard Shading Systems}, journal = {Energy and Buildings}, volume = {50}, year = {2012}, abstract = {

This article evaluates the performance of an integrated micro structural perforated shading screen (MSPSS). Such a system maintains a visual connection with the outdoors while imitating the shading functionality of a venetian blind. Building energy consumption is strongly influenced by the solar gains and heat transfer through the transparent parts of the fenestration systems. MSPSS is angular-dependent shading device that provides an effective strategy in the control of daylight, solar gains and overheating through windows. The study focuses on using direct experimental methods to determine bi-directional transmittance properties of shading systems that are not included as standard shading options in readily available building performance simulation tools. The impact on the indoor environment, particularly temperature and daylight were investigated and compared to three other static complex fenestration systems. The bi-directional description of the systems was used throughout the article. The simulations were validated against outdoor measurements of solar and light transmittance.

}, keywords = {building performance modelling, complex fenestration system, daylight, shading, solar gains}, doi = {10.1016/j.enbuild.2012.03.038}, author = {Appelfeld, David and Andrew McNeil and Svendsen, Svend} } @techreport {1458, title = {High Performance Building Facade Solutions: PIER Final Project Report}, year = {2009}, month = {12/2009}, abstract = {

Building fa{\c c}ades directly influence heating and cooling loads and indirectly influence lighting loads when daylighting is considered, and are therefore a major determinant of annual energy use and peak electric demand. fa{\c c}ades also significantly influence occupant comfort and satisfaction, making the design optimization challenge more complex than many other building systems.

This work focused on addressing significant near-term opportunities to reduce energy use in California commercial building stock by a) targeting voluntary, design-based opportunities derived from the use of better design guidelines and tools, and b) developing and de ploying more efficient glazings, shading systems, daylighting systems, fa{\c c}ade systems and integrated controls.

This two-year project, supported by the California Energy Commission PIER program and the US Department of Energy, initiated a collaborative effort between The Lawrence Berkeley National Laboratory (LBNL) and major stakeholders in the fa{\c c}ades industry to develop, evaluate, and accelerate market deployment of emerging, high-performance, integrated fa{\c c}ade solutions. The LBNL Windows Testbed Facility acted as the primary cata lyst and mediator on both sides of the building industry supply-user business transaction by a) aiding component suppliers to create and optimize cost effective, integrated systems that work, and b) demonstrating and verifying to the owner, designer, and specifier community that these integrated systems reliably deliver required energy performance. An industry consortium was initiated amongst approximately seventy disparate stakeholders, who unlike the HVAC or lighting industry, has no single representative, multi-disciplinary body or organized means of communicating and collaborating. The consortium provided guidance on the project and more importantly, began to mutually work out and agree on the goals, criteria, and pathways needed to attain the ambitious net zero energy goals defined by California and the US.

A collaborative test, monitoring, and reporting protocol was also formulated via the Windows Testbed Facility in collaboration with industry partners, transitioning industry to focus on the import ance of expecting measured performance to consistently achieve design performance expectations. The facility enables accurate quantification of energy use, peak demand, and occupant comfort impacts of synergistic fa{\c c}ade-lighting-HVAC systems on an apples-to-apples comparative basis and its data can be used to verify results from simulations.

Emerging interior and exterior shading technologies were investigated as potential near-term, low-cost solutions with potential broad applicability in both new and retrofit construction. Commercially-available and prototype technologies were developed, tested, and evaluated. Full-scale, monitored field tests were conducted over solstice-to-solstice periods to thoroughly evaluate the technologies, uncover potential risks associated with an unknown, and quantify performance benefits. Exterior shading systems were found to yield net zero energy levels of performance in a sunny climate and significant reductions in summer peak demand. Automated interior shading systems were found to yield significant daylighting and comfort-related benefits.

In support of an integrated design process, a PC-based commercial fenestration (COMFEN) software package, based on EnergyPlus, was developed that enables architects and engineers to x quickly assess and compare the performance of innovative fa{\c c}ade technologies in the early sketch or schematic design phase. This tool is publicly available for free and will continue to improve in terms of features and accuracy. Other work was conducted to develop simulation tools to model the performance of any arbitrary complex fenestration system such as common Venetian blinds, fabric roller shades as well as more exotic innovative fa{\c c}ade systems such as optical louver systems.

The principle mode of technology transfer was to address the key market barriers associated with lack of information and facile simulation tools for early decisionmaking. The third party data generated by the field tests and simulation data provided by the COMFEN tool enables utilities to now move forward toward incentivizing these technologies in the marketplace.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Dennis L. DiBartolomeo and Joseph H. Klems and Robert D. Clear and Kyle S. Konis and Robert J. Hitchcock and Mehry Yazdanian and Robin Mitchell and Maria Konstantoglou} } @article {11918, title = {High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition}, journal = {Thin Solid Films}, year = {2009}, abstract = {

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200{\textdegree}C, have resistivities in the low to mid 10-4Ω cm range with a transmittance better than 85\% in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

}, author = {Andr{\'e} Anders and Sunnie H.N. Lim and Kin Man Yu and Joakim Andersson and Johanna Ros{\'e}n and Mike McFarland and Jeff Brown} } @conference {11927, title = {Highly Insulating Glazing Systems using Non-Structural Center Glazing Layers}, booktitle = {2008 Annual ASHRAE Meeting}, year = {2008}, month = {06/2008}, address = {Salt Lake City, UT}, abstract = {

Three layer insulating glass units with two low-e coatings and an effective gas fill are known to be highly insulating, with center-of-glass U-factors as low as 0.57 W/m2-K (0.10 Btu/h-ft2-{\textdegree}F). Such units have historically been built with center layers of glass or plastic which extend all the way through the spacer system.

This paper shows that triple glazing systems with non-structural center layers which do not create a hermetic seal at the edge have the potential to be as thermally efficient as standard designs, while potentially removing some of the production and product integration issues that have discouraged the use of triples.

}, author = {Dariush K. Arasteh and Howdy Goudey and Christian Kohler} } @techreport {1467, title = {High-Performance Commercial Building Fa{\c c}ades}, year = {2002}, abstract = {

There is a significant and growing interest in the use of highly-glazed fa{\c c}ades in commercial buildings. Large portions of the fa{\c c}ade or even the entire fa{\c c}ade are glazed with relatively high transmittance glazing systems, and typically with some form of sun control as well. With origins in Europe the trend is expanding to other regions, including the United States. A subset of these designs employ a second layer creating a double envelope system, which can then accommodate additional venting and ventilation practices. The stated rationale for use of the these design approaches varies but often includes a connection to occupant benefits as well as sustainable design associated with daylighting and energy savings. As with many architectural trends, understanding the reality of building performance in the field as compared to design intent is often difficult to ascertain. We have been particularly interested in this emerging trend because prior simulation studies have shown that it should be technically possible to produce an all-glass fa{\c c}ade with excellent performance although it is not a simple challenge. The published solutions are varied enough and sufficiently complex that we undertook a year-long international review of advanced fa{\c c}ades to better understand the capabilities and limitations of existing systems and the tools and processes used to create them. This is also intended to create a framework for addressing the missing tools, technologies, processes and data bases that will be needed to turn the promise of advanced fa{\c c}ades into realities. This summary, available as a PDF file and a web site, reports those findings.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Christian Kohler and Vladimir Bazjanac and Vorapat Inkarojrit} } @conference {11913, title = {High Performance Glazing Systems: Architectural Opportunities for the 21st Century}, booktitle = {Glass Processing Days 99 Conference}, year = {1999}, month = {06/1999}, address = {Tampere, Finland}, abstract = {

Glazing systems will fulfill important new roles in buildings in the 21st century. This paper provides an overview of three different functional impacts for advanced glazing systems. New technology and better integration with daylighting and climate control systems allow advanced glazings in building facades to 1) improve the comfort and performance of building occupants, 2) add value and reduce energy operating costs for building owners, and 3) assist in national and global efforts to reduce greenhouse gas emissions that contribute to global warming.

}, author = {Stephen E. Selkowitz} }